Control valve for fluid-operated motors



March 8, 1955 c. J. coBERLY CONTROL VALVE FOR FLUID OPERATED MOTORS 3 Sheets-Sheet l Filed Dec. l, 1949 5:/ #/5 ,4free/verb.

HAP/evs, IZ/gcu, Fos rg@ @BZW/5 March 8, 1955 c. J. coBERLY CONTROL VALVE FOR FLUID OPERATED MOTORS 3 Sheets-Sheet 2 FZ'G.

Filed Dec. l, 1949 March s, 1955 C, J COBERLY 2,703,585

CONTROL VALVE FOR FLUID OPERATED MOTORS 87 Hfs A rroeA/ers United States Patent O CONTROL VALVE FOR FLUID-OPERATED MOTORS Clarence J. Coberly, Los Angeles, Calif., assignor, by mesne assignments, to Kobe, Inc., Huntington Park, Calif., a corporation of California Application December 1, 1949, Serial No. 130,533

11 Claims. (Cl. 137-622) This invention relates in general to duid-operated pumps of the displacement type and a primary object thereof is to provide an improved control valve for a pump of this type.

Fluid-operated pumps are used extensively in the oil industry for pumping oil and other lluids from wells and comprise coupled fluid motor and pump units set in the Wells at the levels from which well lluid is to be pumped. The uid motor unit includes a motor piston reciprocable in a motor cylinder and is actuable by an operating iiuid, such as oil, under relatively high pressure which is delivered thereto through a supply tubing extending downwardly into the well from the surface. The fluid motor unit also includes a motor valve for regulating delivery of operating fluid to the motor cylinder in such a manner as to apply to the motor piston fluid pressure diiferentials tending to displace the motor piston rst in one direction and then in the opposite direction so as to reciprocate the motor piston in its cylinder. The pump unit of such a fluid-operated pump includes a pump piston which is reciprocable in a pump cylinder to draw well fluid into the pump cylinder from the well and to discharge such Well fluid therefrom as production lluid into a production tubing set in the well and leading upwardly-to the surface, the motor and pump pistons being coupled together so that reciprocatory movement of the former is communicated to the latter.

An important object of the invention is to provide an improved motor valve construction for such a uid-operated pump.

More specifically, an important object of the invention is to provide a motor valve whose components need not be machined accurately so as to reduce manufacturing costs. I prefer to accomplish this by making various elements of the motor valve self-aligning, whichis another object of the invention.

Another object is to provide a motor valve having a generally tubular valve member which is reciprocable in the valve body and which includes a pair of elements so connected as to provide for limited relative lateral movement therebetween, thus rendering such elements of the valve member self-aligning.

A further object is to provide a motor valve having a oating valve bushing which is laterally movable relative to the valve body to provide for proper alignment of the valve bushing with respect to the elements of the valve body.

Yet another object is to provide a motor valve havingl a oating valve rod to provide for proper alignment of the valve rod with other components of the valve.

The foregoing objects of the invention and the advantages suggested thereby, together with various other objects and advantages which will become evident, may be attained through the exemplary embodiments illustrated in the acompanying drawings, which are for the purpose of illustration only, and described in detail hereinafter. Referring to the drawings:

Fig. 1 is a utility view illustrating a uid-operated pump which embodies the invention as installed in a well;

Figs. 2, 3 and 4 are enlarged vertical sectional views of the pump, Figs. 3 and 4 being downward continuations of Figs. 2 and 3, respectively, and Figs. 2 and 3 being on a arger scale than Fig. 4;

Fig. 5 is a vertical sectional view duplicating portions lFigs. 2 and 3 on a reduced scale, but illustrating other .rating positions for various components of the pump; "gs. 6, 7, 8 and 9 are transverse sectional viewsrespec- 2,703,585 Patented Mm s, 1955 tively taken along the broken lines 6-6, 7--7, 8-8 and 9-9 of Figs. 2 and 3 of the drawings; and

Fig. 10 is a transverse sectional view taken along the broken line 11)*10 of Fig. 4 of the drawings.

Referring particularly to Fig. l of the drawings, the numeral 21 designates a well casing which is set in an oil well with its lower end open to an oil producing zone of the well, as by being provided with perforations therein through which oil and other uids from oil producing formations surrounding the well may enter the interior of the casing. Connected to the upper end of the casing 21 is a casing head 22 having a tubing head 23 mounted thereon and rigidly connected thereto. Suspended from the tubing head 23 and extending downwardly into the casing 21 is a production tubing 24 which is provided at its lower end with an intake fitting 25. The intake fitting provides a tapered seat 26 for a fluid-operated pump 27 which embodies the invention, and is provided with an intake passage 28 therethrough for conveying well fluid from the interior of the casing 21 to the intake of the ,v pump. A check valve 29 prevents outow through the passage 28.

The pump 27, in the particular construction illustrated, is of the so-called free type in that it is movable hydraulically through a supply tubing 30 between the surface of the ground and an operating position wherein it is seated on the pump seat 26. The tubing 30 is also suspended from the tubing head 23 and extends downwardly into the tubing 24, direct fluid communication between the tubings 24 and 30 being prevented when the pump 27 is in its operating position by a pair of annular sealing elements 31 which, as shown in Fig. 2 of the drawings, are carried by the pump and are adapted to engage the interior wall of the tubing 30. Although I have illustrated and described the invention in connection with a pump of the free type, l do not intend to be limited thereto.

The tubing 30 is adapted to convey operating uid under pressure downwardly to the pump 27 to actuate it as will be discussed in more detail hereinafter, the operating fluid under pressure being delivered to the supply tubing through a pipe 36 which is connected to the tubing head 23 in communication with the supply tubing. The well fluid entering the pump 27 through the inlet fitting 25 is discharged into the production tubing 24 as production fluid and is conveyed upwardly thereby to the surface. The production fluid flows from the production tubing 24 into a pipe 37 which is connected to the tubing head 23 in liuid communication with the production tubing. As will become apparent, the operating fluid is also discharged into the production tubing 24 after it has actuated the pump 27, although it will be understood that the spent operating fluid may be conveyed to the surface separately from the production fluid. A vent pipe 38 is connected to the casing head 22 and communicates with the interior of the casing 21 so that gas may be drawn olf from the top of the casing or pressure applied thereby.

As is well known in the art, the pump 27 may be removed from the well hydraulically by introducing the operating uid under pressure into the production tubing 24, rather than into the supply tubing 30. The pressure of the operating uid introduced into the production tubing 24 acts on an annular area 39 at the lower end of the pump 27 to unseat the pump, the pressure of the operating fluid thereafter being appliedto the entire area of the pump to move it upwardly through the supply tubing 30 to the surface. As will be understood, the check valve 29 closes to prevent loss of iluid from the tubing 24 Connected to the upper end of the tubing head 23 in alignment with the supply tubing 30 is a tube 40 for receiving the pump 27 when it reaches the surface, the tube 40 being provided with means (not shown) for retaining the pump when it reaches the surface, as by engaging a conical head 41 at the upper end of a packer mandrel 42 which extends upwardly from the body of the pump. The packer mandrel 42 carries packers 43 which are adapted to expand into engagement with the interior wall of the supplyvtubing 30 to prevent upward ow of fluid past the pump 27 during the operation of removing the pump from the well. When the pump 27 is in its operating position and operating fluid under pressure is being delivered thereto through the supply tubing 30, the packers 43 contract to permit downward flow of operating fluid to the pump.

The foregoing completes u general description of an installation in which the fluid-operated pump 27 embodying the invention may be incorporated and the pump 27 will now be considered in detail with particular rer"- erence to Figs. 2, 3 and 4 of the drawings. As shown in Fig. 2 of the drawings, the body of the pump 27 is provided at its upper end with a fitting 45 onto the lower end of which is threaded a tube providing a motor cylinder 46 for a motor piston 47. The fitting 45 carries the aforementioned annular sealing elements 31, which are respectively disposed on opposite sides of an external annular groove 48 in this fitting. When the pump 27 is in its operating position, the annular groove 48 communicates with the interior of the production tubing 24 through radial ports 49 in the supply tubing 35. The f1tting 45 is provided with radial ports 58 therein which communicate at their outer ends with the annular groove 48 and at their inner ends with a counterbore 51 in the fitting, the counterbore 51 communicating with the upper end of the motor cylinder 46 so that the fluid pressure in the upper end of the motor cylinder is always equal to the pressure of the column of production fluid in the production tubing 24.

Centrally disposed in the motor cylinder 46 and encompassed by the motor piston 47 is a tubular valve rod 55 which, as will be discussed in more detail hereinafter, forms part of a main valve mechanism 56 of the pump 27, the main valve being carried by the motor piston in the particular construction illustrated. The valve rod 55 constitutes a pilot valve means of the invention. From the motor cylinder 46, the valve rod 55 extends upwardly through the counterbore 51 in the fitting 45 and through a bore 57 in this fitting into a counterbore 58 therein, the valve rod 55 having a reduced-diameter portion 59 of smaller diameter than the diameter of the bore 57 so as to provide a clearance therebetween. The valve rod 55 is provided at its upper end with a head 60 which is disposed in the counterbore 58 and which is of smaller diameter than the counterbore to provide a clearance therebetween, an annular sealing element 61 being disposed between the head 60 and the walls of the counterbore 58. It will be apparent that, with this con struction, the valve rod 55 is free to move laterally relative to the body of the pump 27 to a limited extent to compensate for any inaccuracies in manufacture which affect concentricity, which is an important feature of the invention.

Axial movement of the valve rod 55 downwardly is prevented by engagement of the head 60 thereon with the base of the counterbore 58 in the fitting 45, and axial movement thereof upwardly is prevented by engagement of the head 60 with the lower end of the packer mandrel 42, which is threaded into the counterbore 58. The packer mandrel is threaded into the counterbore 58 a distance suflicient only to prevent any substantial axial movement of the valve rod, but insuflicient to prevent lateral movement thereof. As will be noted, the packer mandrel 42 is tubular, the packer mandrel communicating at its upper end with the supply tubing through ports 64, Fig. 1, and communicating at its lower end with the tubular valve rod 55. Thus, the fluid pressure in the tubular valve rod 55 is always substantially the pressure of the operating fluid in the supply tubing 30.

The motor piston 47 includes a valve body 65 which forms part of the main valve 56 and which includes upper and lower tubular elements 66 and 67, respectively, the tubular element 66 having a cap 68 threaded thereon at its upper end. Threaded onto the lower end of the tubular element 66 and encompassing the tubular element is an outer sleeve 69 of the motor piston 47, this sleeve being in slidable, fluid-tight engagement with the motor cylinder 46 throughout the major portion of the length of the sleeve. The upper end of the outer sleeve 69, the upper tubular element 66 and the cap 68 are of smaller diameter than the motor cylinder 46 to provide an annular space 70 which continuously communicates with the upper end of the motor cylinder and which thus continuously contains fluid subjected to the production column pressure.

Threaded into the lower end of the lower tubular element 67 is an inner sleeve 73 of the motor piston 47,

the inner sleeve being spaced inwardly from the outer sleeve 69 to provide an annular space 74 therebetween and being spaced outwardly from the valve rod 55 to provide an annular space 75 therebetween. Threaded into the lower end of the inner sleeve 73 is a tubular pump piston 76, Fig. 4, which is reciprocable in a pump cylinder 77 adapted to communicate with the intake passage 28 in a manner not specifically shown, the pump piston being closed at its lower end, as by a plug 78 threaded thereinto. As will be apparent, the lower end of the tubular valve rod 55 communicates with the interior of the pump piston 76 so that the interior of the pump piston continuously contains operating fluid under pressure. The operating fluid thus continuously applies a downward force to the pump piston. The annular space 75, between the inner sleeve 73 of the motor piston 47 and the valve rod 55, communicates at its lower end with the interior of the pump piston 76 so that it always contains operating fluid under pressure.

In order to prevent axial movement of the lower tubular element 67, it is provided with a head 81 thereon, Fig. 3, which is disposed between the lower end of the tubular element 66 and an internal annular flange 82 on the outer sleeve 69. The outer sleeve 69 is threaded onto the tubular element 66 an extent sufficient to prevent substantial axial movement of the tubular element 67. Fluid leakage between the lower tubular element 67 and the outer sleeve 69 is prevented by an annular sealing element 83 carried by the head 81. By making the valve body 65 in the two parts 66 and 67, standard tube stock can be used, thus avoiding a costly and dilllcult axial drilling operation heretofore required with one-piece valve bodies used for similar purposes.

The main valve 56 includes a tubular valve bushing 85 which is disposed in the valve body 65 and through which the valve rod 55 extends in slidable, fluid-tight engagement. The valve bushing 85 is restrained axially by disposing an annular flange 86 thereon between the upper end of the upper tubular element 66 of the valve body and an internal annular flange 87 on the cap 68, an annular sealing element 88 being disposed between the annular flange on the valve bushing and the cap 68 to prevent fluid leakage therebetween. As will be noted, the valve bushing 85 is of smaller diameter than the cap 68 to permit limited lateral movement of the valve bushing relative to the cap to compensate for any lack of concentricity, which is an important feature of the invention. The cap 68 is threaded onto the upper tubular element 66 of the valve body 65 a distance sufficient only to prevent substantial axial movement of the valve bushing, but insucient to prevent lateral floating movement thereof.

The main valve 56 includes a reciprocable main valve member 91 of the differential-area, two-speed, throttling type which is disposed in the valve body 65 on the valve bushing 85. The main valve member 91 includes a major portion which is disposed in a major bore 92 in the upper tubular element 66 of the valve body and which is in slidable, fluid-tight engagement with the upper tubular element 66 and with the valve bushing 85. The main valve member 9,1 also includes a minor portion which is disposed in a minor bore 93, Fig. 3, in the lower tubular element 67 of the valve body 65 and which is in slidable, fluid-tight engagement with the lower tubular element 67.

The main valve member 91 comprises upper and lower tubular elements 94 and 95, Figs. 2 and 3, the former constituing the aforementioned major portion of the valve and the latter constituting the aforementioned minor portion thereof. The upper and lower tubular elements 94 and 95 are connected in a manner permitting limited relative lateral movement therebetween to compensate for any lack of concentricity, which is an important feature of the invention. The element 95 is provided with a tubular projection 96 which is disposed in a recess 97 in the element 94, the diameter of the projection 96 being less than the diameter of the recess 97 to permit relative lateral movement. Leakage between the two elements 94 and 95 is prevented by an annular sealing eley ment 98 which encircles the stem 96 and engages the peripheral wall of the recess 97. No connecting mean. for preventing axial separation of the upper and lowl tubular elements 94 and 95 is required since the il pressures acting on the upper end of the upper elem and the lower end of the lower element hold these ments in assembled relation. Axial insertion of the projection 96 into the recess 97 is limited by a shoulder 99 on the lower tubular element 95 which engages the lower end of the upper tubular element 94. By making the main valve member 91 in the two parts 94 and 95 standard tube stock can be used, thus simplifying construction and reducing the cost thereof.

In operation, the interior of the pump piston 76 is, as previously indicated, in continuous communication with the supply tubing through the tubular valve rod 55 so that the pressure of the operating lluid continuously acts downwardly on the pump piston, the net area on which the operating lluid in the pump piston acts downwardly being equal to the external cross-sectional area of the valve rod. IAlso, as indicated previously, the upper end of the motor cylinder 46 is in continuous communication with the production tubing 24 so that the upper end of the motor piston is continuously exposed to the production column pressure, the latter pressure acting on an annular area at the upper end of the motor piston which is equal to the diierence between the crosssectional area of the motor piston and the external crosssectional area of the valve rod. The lower annular end of the motor piston is alternately exposed to the operating fluid and production column pressures by the main valve 91 in a manner to be described hereinafter, the area on the lower end of the motor piston to which the operating iluid and production column pressures are alternately applied being equal to the diierence between the crosssectional area of the motor piston and the external crosssectional area of the pump piston 76. As will be apparent, when the annular area at the lower end of the motor piston 47 is exposed to the production column pressure, the motor and pump pistons are moved downwardly by the action of the operating fluid within the pump piston applied to the area of the valve rod. Conversely, when the annular area at the lower end of the motor piston is exposed to the operating fluid pressure, the motor and pump pistons are moved upwardly, the annular area at the lower end of the motor piston being greater than the external cross-sectional area of the valve rod 55 to accomplish this.

The main valve member 91 is reciprocable between an Aupper position wherein it connects the lower end of the motor cylinder 46 with the upper end thereof to apply the production column pressure to the annular area at the lower end of the motor piston, and a lower position wherein it connects the lower end of the motor cylinder with the interior of the pump piston 76 to apply the operating uid pressure to the annular area at the lower end of the motor piston. The upper and lower .positions of the main valve member 91 are shown in Figs. 2 and 3 and in Pig. 5 of the drawings, respectively. Referring to Figs. 3 and 8 of the drawings, the lower element 95 of the member 91 is provided with external passages 102 therein which span radial ports l0 3 and 104 when the valve member is in its upper positlon. As shown in Fig. 3 of the drawings, and as best shown 1n Fig. 8 thereof, the radial ports 103 extend through the upper tubular element 66 of the valve body 65 and the outer sleeve 69 of the motor piston 47 to connect the passages 102 with the annular space 70 leading to the upper end of the motor cylinder 46 when the mam valve member 91 is in its upper position. The radlal ports 104 extend through the lower tubular element 67 of the valve body 65 to connect the annular space 74 between the outer sleeve 69 and the inner sleeve 73 of the motor piston to the passages 102 when the main valve member 91 is in its upper position. The annular space 74 leads to the lower end of the motor cylinder 46 so that, when the valve member 91 is in its upper position, annular area at the lower end of the motor piston 47 is exposed to the production column pressure continuously obtaining in the upper end of the motor cylinder through the annular space 70, the radial ports 103, the passages 102 in the main valve member 91, the radial ports 104 and the annular space 74. Under such conditions, the motor and pump pistons 47 and 76 move downwardly as a unit in their respective cylinders 46 and 77.

Referring to Fig. 5 of the drawings, when the main valve member 91 is in its lower position, the passages 102 therein connect the radial ports 104 to achamber 105 in the lower tubular element 67 of the valve body 65, this chamber being in continuous communication with the interior of the pump piston 76 through the annular space 75 between the valve rod 55 and the inner sleeve 73 of the motor piston 47. Under such conditions, since the fluid pressure within the pump piston 76 is always the operating tuid pressure, the annular area at the lower end of the motor piston 47 is exposed to the operating fluid pressure through the annular space 75, the chamber 105, the passagesg102, the radial ports 104, and the annular space 74 between the outer and inner sleeves 69 and 73.

Referring to "Fig, 2 of the drawings, when the main valve member 91 is in its upper position, it connects the lower end of the motor cylinder 46 to the production column pressure in the manner hereinbefore described so as to effect the downward stroke of the motor and pump pistons 47 and 76. The main valve member 91 is held in its upper position during the entire downstroke of the pistons by a uid pressure differential impressed thereacross, the lower end of the valve member, which is of relatively small area, being continuously exposed to the operating iluid pressure in the chamber 105, and the upper end of the valve member, which is of relatively large area, being exposed to the production column pressure during the downstroke of the motor and pump pistons in a manner about to be described. The main valve member 91 is provided with an external annular channel which registers with radial ports 111 in the upper tubular element 66 of the valve body 65 when the Valve member is in its upper position, the radial ports 111 communicating with the production column pressure obtaining in the annular space 70 between the valve body and the wall of motor cylinder 46. The main valve member 91 is provided with an internal annular channel 112 which is connected to the external annular channel 110 by radial ports in the valve member, the internal annular channel 112 communicating with another internal annular channel 114 through an internal helical groove 115 in the valve member. The internal annular channel 114 in the main valve member communicates with an internal annular groove 116 therein, which groove communicates through radial ports with an external annular channel being formed by reducing the diameter of the upper end of the valve member slightly. Thus, the main valve member 91 is maintained in its upper position during the downstroke of the motor and pump pistons by exposing the upper end of the valve member to the production column pressure through the radial ports 111, the external annular channel 110, the internal annular channel 112 and connecting radial ports, the in-A ternal helical groove 115, the internal annular channel 114, the internal annular groove 116 and the external annular channel 117 and connecting radialports.

'Referring to Fig. 5 of the drawings, when the motor and pump pistons 47 and 76 approach the end of the downstroke, the lower end of the valve rod 55 uncovers radial ports 120, see Fig. 2 also, in the valve bushing 85 to admit operating fluid under pressure thereinto. The ports 120 communicate at their outer ends with an external'groove 121, which groove communicates with the internal annular channel 114 in the main valve member 91 when the main valve member is in its upper position, as shown in Fig. 2 of the drawings. Thus, when the motorand pump pistons reach the end of the downstroke, the operating fluid pressure is applied to the upper end of the main valve member 91 to move it downwardly into its lower position, as shown in Fig. 5 of the drawings, by way of the radial ports 120 and the groove 121, the internal annular channel 114 in the valve member 91, the internal annular groove 116 in the valve member, the external annular channel 117 and the radial ports connecting the groove 116 and channel 117. With the main valve member 91 in its lower position, the operating fluid pressure is applied to the annular area at the lower end of the motor piston 47 to effect the upstroke of the motor and pump pistons. The operating fluid pressure is applied to the upper end of the main Valve member 91 during the upstroke of the motor and pump pistons to hold the valve member in its lower position by way of the internal helical groove 115 in the valve member, the internal annular channel 114 therein, the internal annular groove 116 therein and the radial ports connecting this groove to the external channel 117. Under such conditions, the operating fluid pressure is communicated to the lower end of the internal helical groove 115 through 7 an annular clearance between the valve member 91 and the valve rod S5.

When the motor and pump pistons 47 and 76 reach the end of the upstroke, the lower end of the reduced diameter portion 59 of the valve rod 55 registers with radial ports 122 in the valve bushing 85, these radial ports communicating through a groove 123 with the upper end of the main valve member 91. Thus, the upper end of the main valve member is exposed to the production column pressure obtaining in the counterbore 51 in the upper litting 45 to permit the valve member to move upwardly into its upper position. As previously discussed, this edects the downstroke of the motor and pump pistons. It will thus be understood that the valve rod 55 acts as a pilot valve in response to movement of the piston assembly to control the application of iluid pressure to the large upper end of the main valve 91.

Although I have disclosed an exemplary embodiment oi my invention for purposes of illustration, it will be understood that various changes, modications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention.

-I claim as my invention:

l. In a control valve for a duid-operated motor, the combination of: a tubular valve body, including a pair of valve body elements substantially axially aligned; a lateral-lost-motion connection connecting said valve body elements together; tubular main valve means disposed in said valve body; and pilot valve means extending into said main valve means for applying a fluid pressure dilerential to said main valve means to move said main valve means axially.

2. `In a control valve for a fluid-operated motor, the combination of: a tubular valve body; a tubular valve bushing extending into said valve body; a lateral-lostmotion connection connecting said valve bushing and said valve body together and providing limited lateral movement therebetween; tubular main valve means disposed in said valve body radially between said valve body and said valve bushing; and pilot valve means extending into said valve bushing for applying a duid pressure differential to said main valve means to move said main valve means axially.

3. lIn a control valve for a duid-operated motor, the combination of: a tubular valve body; tubular main valve means disposed in said valve body, including a pair of tubular valve elements substantially axially aligned; a lateral-lost-motion connection connecting said valve elements together and providing limited lateral movement therebetween; and pilot valve means extending into said main valve means for applying a fluid pressure dilerential to said main valve means to move said main valve means axially.

4. in a control valve for a fluid-operated motor, the y combination of: a tubular valve body, including a pair of valve body elements substantially axially aligned; a lateral-lost-motion connection connecting said valve body elements together and providing limited lateral movement therebetween; tubular main valve means disposed in said valve body; pilot valve means extending into said main valve means for applying a -uid pressure dilerential to said main valve means to' move said main Valve means axially; and another lateral-lost-motion connection connecting said pilot valve means to said valve body and providing limited lateral movement between said valve body and said pilot valve means.

5. In a control valve for a fluid-operated motor, the combination of: a tubular valve body, including a pair of valve body elements substantially axially aligned; a lateral-lost-motion connection connecting said valve body elements together and providing limited lateral movement therebetween; a tubular main valve means disposed in said valve body; a tubular valve bushing extending into said main valve means; another lateral-lost-motion connection connecting said valve bushing and said valve body together and providing limited lateral movement therebetween; and pilot valve means extending into said valve bushing for applying a liuid pressure differential to sald main valve means to move said main valve means axia y.

6. In a control valve for a duid-operated motor, the combination of: a tubular valve body, including a pair ot" valve body elements substantially aligned; means connecting said valve body elements together; tubular main valve means disposed in said valve body, including a pair of tubular valve elements substantially axially aligned; a lateral-lost-motion connection connecting said valve elements together and providing limited lateral movement therebetween; and pilot valve means extending into said main valve means for applying alluid pressure differential to said main valve means to move said main valve means axially.

7. In a control valve for a duid-operated motor, the combination of: a tubular valve body, including a pair of valve body elements substantially axially aligned; means connecting said valve body elements together; tubular main valvemeans disposed in said valve body, including a pair of tubular valve elements substantially axially aligned; a lateral-lost-motion connection connecting said valve elements together and providing limited lateral movement therebetween; a tubular valve bushing extending into saidtmain valve means; another laterallost-motion connection connecting said valve bushing and said valve body together and providing limited lateral movement therebetween; and pilot valve means extending into said main valve means for applying a fluid pressure differential to said main valve means to move said main valve means axially.

8. In a control valve for a duid-operated motor, the combination of: a tubular valve body, including a pair of valve body elements substantially axially aligned; a lateral-lost-motion connection between said valve body elements; means providing a fluid-tight seal between said valve body elements; tubular main valve means disposed in said valve body; and pilot valve means extending into said main valve means for applying a fluid pressure differential to said main valve means to move said main valve means axially.

9. In a control valve for a duid-operated motor, the combination of: a tubular valve body; a tubular valve bushing extending into said valve body; a lateral-lostmotion connection connecting said valve bushing and said valve body together and providing limited lateral movement therebetween; means providing a iluid-tight seal between said valve body and said valve bushing; tubular main valve means disposed in said valve body radially between said valve body and said valve bushing; and pilot valve means extending into said valve bushing for applying a fluid pressure` differential to said main valve means to move said main valve means axially.

10. In a control valve for a duid-operated motor, the combination of: a tubular valve body; tubular main valve means disposed in said valve body, including a pair of tubular valve elements substantially axially aligned; a lateral-lost-motion connection connecting said valve elements together and providing limited lateral movement therebetween; means providing a fluid-tight seal between said Valve elements.; and pilot valve means extending into said main valve means for applying a iluid pressure differential to said main valve means to move said main valve means axially.

Il. In a control valve for a duid-operated motor, the combination of a plurality of tubular elements which have substantially coinciding axes and which are arranged in at least two radially spaced pairs; and lateral-lostmotion connections between the elements of the respective pairs and providing limited relative lateral movement between the elements of the respective pairs.

References Cited inthe tile of this patent UNITED STATES PATENTS 677,13-7 Leavitt June 25, 1901 2,005,995 Knox lune 25, 1935 2,081,222 Coberly May 25, 1937 2,119,736 Coberly lune 7, 1938 2,191,093 Coberly Feb. 20, 1940 2,327,571 Wallis Aug. 24, 1943 2,327,572 Wallis Aug. 24, 1943 2,365,574' McWave Dec. 19,` 1944 2,473,864 Coberly lune 21, 1949 2,497,348 Ecker Feb. 14, 1950 2,501,380 Dempsey Mar. 21,` 1950 FOREIGN PATENTS 861,377 France Feb. 7, 1941 

